Means for assuring the safe working of automatic pressure die-casting apparatus



Nov. 20, 1934. K. F. WAGNER 1,981,381

MEANS FOR ASSURING THE SAFE WORKING OF AUTOMATIC PRESSURE DIE CASTING APPARATUS Filed Oct. 10. 1951 Mai/r cam reared air-Zine :75 '1' re frvm limb/y- Air exhaust cantor: Karl Elba/7'20 Wggnef one pair or and as controls Patented Nov. 20, 1934 PATENT OFFICE.

MEANS FOR ASSURING THE SAFE WORKING 0F AUTOMATIC PRESSURE DIE-CASTING APPARATUS Karl Friedrich Wagner, Stuttgart,

mesne assignments,

signer, by

Development Corporation,

poration of Delaware Germany, asto Magnesium Newark, N. 1., a cor- Application October 10, 1931, Serial No. 568,033

In Germany 14 Claims.

The present invention relates to a method of and means for assuring the safe working of automatic pressure die-casting apparatus, and is a continuation in part of my co-pending application Serial No. 559,249 filed August 25, 1931, and entitled Automatic die-casting apparatus.

In the said application Serial No. 559,249 I have described and claimed apparatus for assuring the safe operation of automatic pressure diecasting apparatus, in which a special working stage is interposed between the stage which is to be rendered safe and the next stage in succession, which stops the machine when the conditions for safe continuance of working are lacking, i. e. when the preceding stage of operation has not been correctly and completely performed, but otherwise allows the next working stage to proceed. Such safeguarding means are, inter alia, provided for the stage of admitting the injection pressure to the molten metal in the pres--, sure chamber so as to fill the mold.

In further developing the idea underlying the inVention it has been found that there is no need to stop the entire machine when the conditions for the safe admission of the injection pressure are absent, but that it is suflicient to prevent the injection pressure from acting upon the molten metal present in the pressure chamber.

According to the present invention, this is accomplished by interrupting the operative connection between the valve which admits the injection pressure into the pressure chamber, and

the cam allotted to that working stage, when, and so long as, the conditions for the safe continuance of working are absent.

In order to more clearly understand the nature of the invention, reference is made to the accompanying drawing, which illustrates diagrammatically and by way of example, a suitable embodiment of an apparatus according to the present invention in which Fig. 1 represents a casting machine and valve control mechanism in partial sectional elevation, and Fig. 2 represents a fragmentary ground plan view in partial section taken along the line A-A of Fig. 1.

In the drawing forming a part of this application a is a valve box containing a plurality of reciprocally working pairs of valves of which the admittance of pressure to the pressure chamber. This pair of valves is actuated by means of two cams b1 and b1 mounted opposite to each other on two continually rotating camshafts Bl and B2 which are held in registration by suitable means (not October 11, 1930 shown) The cams, by means of a roller 0 mounted on the operating arm of a triple-arm lever d, suspended between said cams and pivoted at e, cause the said lever to perform an oscillatory movement which, under regular conditions to be described below results in an alternate actuation of the valves constituting a pair by means of tappets {1 and 12. In this manner an upward movement of the left free arm of the triple-arm lever results in opening valve (ll while valve (12 is closed, thus admitting injection pressure to the pressure chamber, whereas a downward movement of the said left arm closes valve or, while the right arm, by its upward movement, relieves the pressure acting on the pressure chamber by opening valve (12.

A rigid structure consisting of a pair of pressure plates in and n2, rigidly secured to suitable transverse column membersli and la, is movably guided within the main frame of the casting machine, the transverse column members simultaneously serving as guides for an intermediate pressure plate m. On the upper surface of the latter a die-closing cylinder 2, provided with pressure inlets w and .r and corresponding pressure outlets m1 and :01 (indicated by arrows), is mounted, while the under surface of the plate m has secured thereto the upper mould part 01. On the upper surface of the pressure plate 111 a locking cylinder 1), provided with pressure inlets u and v and pressure outlets in and 01 (indicated by arrows), is mounted, said cylinder reciprocating with a piston 1/1 rigidly attached to the frame of the casting machine, whereas the lower surface of the plate 111 has secured thereto a depending piston 21 adapted to operate within the aforementioned cylinder 2. Supported upon the upper surface of the pressure plate 122 is the lower part of the mould 02, which portion of the mould is adapted to be brought into registry and close contact with the mouth or nozzle t of the pressure chamber.

Prior to a casting operation the mould parts 01 and 0: are open and the lower mould part is removed from the mouth or nozzle t.of the pressure chamber. To close the mould and place the machine in proper condition to perform a casting operation fluid pressure is admitted through inlet a: into the cylinder 2, which action results in lowering the intermediate pressure plate m towards the lower pressure plate m, thereby closing the mould parts 01 and 0a. Thereupon fluid pressure is admitted through inlet 0 into cylinder g, which causes the entire pressureplate aggregate (m, n: and m) to move as a unit towards and into contact with the nozzle t.

To remove the mould from the pressure chamber on completion of a casting operation or metal injection process, and to open the mould, the foregoing operations are performed in an inverse order, the fluid pressure being admitted to cylinder y and cylinder 2 through the inlets u and w respectively. It will be understood that the outlet or exhaust valves m, m and 101, 1:1 function in proper order with respect to the inlet valves u, v and :r, w.

According to the present invention the triplearm lever d, which is pivoted at e, is provided with a slide 9 and can only cause the opening of the valve Ctr admitting pressure to the pressure chamber when the said slide is completely in position under the corresponding tappet f1. Said slide is pressed and set under tension against the action of the counter spring k by the upward movement of the pressure plate in as the mould is raised out of contact with the nozzle t of the pressure chamber, said upward movement causing the bell-crank lever h to press against the flat nose or end oftthe slide 9. At the same time, the pawls i1 and i2 engage in two notches in the slide and retain it in that position. If the mould parts 01 and 02 are closed, as previously described, and the prescribed locking pressure is attained in cylinder 11, which pressure is also transmitted to the under side of piston 10, the piston p will overcome the correspondingly calculated pressure of the spring q and withdraw the pawl i2. 0n the mould being properly placed in position on the mouth t of the pressure chamber, the striker pin 1' attached to the intermediate pressure plate m, also withdraws the pawl h, by means of the one-armed lever s, so that the solid portion of the slide g moves into position under the admission valve or thereby enabling said valve to be actuated by the cam.

On the other hand, if either the pressure be inadequate, or the complete closing of the mould be prevented through any other cause, the pawls will not be withdrawn, the slide remaining under tension, and the moving of the lever pivoted at e will not actuate the admission valve.

I claim:

1. In automatic pressure die-casting apparatus having a multipart mould, a pressure chamber, mechanical means for closing said mould and for contacting the mould with said pressure chamber, and pressure means for establishing tight connection between the individual parts of said mould and between the mould and said pressure chamber, a safety control mechanism comprising, in operative combination, a pressure-admitting valve and an exhaust valve constituting a pair of valves for controlling injection pressure to said pressure chamber, a pair of continually rotating shafts disposed adjacent said valves and supporting a pair of cams, a triple-arm lever suspended between and actuated by said cams so as to perform an oscillatory movement, thereby normally causing its free arms to alternately actuate said pair of valves, and means mounted in said triplearm lever for intercepting the actuation of at least one of said valves by the movement of said lever upon the failure of either the aforesaid mechanical means for closing the mould and contacting said mould with said pressure chamber to complete its action or of said pressure means for establishing tight connection between the individual parts of said mould and between the mould and said pressure chamber to attain a predetermined standard pressure.

2. In automatic pressure die-casting apparatus having a movable multipart mould, a stationary pressure chamber, mechanical means for closing said mould and contacting said mould with said pressure chamber, and pressure means for establishing a tight connection between the individual parts of said mould and between the mould and said pressure chamber, a safety control mechanism comprising, in operative combination, a pressure-admitting valve and an exhaust valve constituting a pair of valves for controlling injection pressure to said pressure chamber, a pair of continually rotating shafts disposed adjacent said valves and supporting a pair of cams, a tripie-arm lever suspended between and actuated by said cams so as to perform an oscillatory movement adapted to actuate said pair 01 valves, a slide mounted in said triple-arm lever, resilient means for normally holding said slide in a position adapted to actuate the pressure admitting valve, a pawl engaging said slide in a position intercepting actuation of the pressure admitting valve and adapted to be disengaged by one part of the mould if and when the mould is properly closed and is in position of contact with the pressure chamber, and another pawl independently engaging said slide in position intercepting actuation of the pressure admitting valve and adapted to be disengaged if and when a standard sealing pressure tightly connecting the individual parts of said mould, and the mould with said pressure chamber, is attained,

3. In automatic pressure die-casting apparatus having a movable multipart mould, a stationary pressure chamber, mechanical means for closing said mould and contacting said mould with said pressure chamber, and pressure means for establishing a tight connection between the individual parts of said mould and between the mould and said pressure chamber, a safety control mechanism comprising, in operative combination, a pressure-admitting valve and an exhaust valve constituting a pair of valves for controlling injection pressure to said pressure chamber, a pair of continually rotating shafts disposed adjacent said valves and supporting a pair of earns, a triple-arm lever suspended between and actuated by said cams so as to perform an oscillatory movement adapted to actuate said pair of valves, a slide mounted in said triple-arm lever, resilient means for normally holding said slide in a position adapted to actuate the pressure admitting valve, a pawl engaging said slide in a position intercepting actuation of the pressure admitting valve and adapted to be disengaged by one part of the mould if and when the mould is properly closed and is in position of contact with the pressure chamber, another pawl independently engaging said slide in position inter cepting actuation of the pressure admitting valve and adapted to be disengaged if and when a standard sealing pressure tightly connecting the individual parts of said mould, and the mould with said pressure chamber, is attained, and means for moving said slide into a position adapted to engage said slide by said pawls, said moving means being actuated by a part of said mould upon opening of the mould.

4. In automatic pressure die-casting apparatus having a mould, a pressure chamber, and means for eilecting a tight connection between said mould and said pressure chamber, a safety control mechanism comprising, in operative combination, a pressure-admitting valve and an exhaust valve constituting a pair of valves for contight trolling injection pressure to said pressure chamber, operating means adapted to normally actuate said pair of valves alternately, and means in-- dependent of said ope-rating means for interrupting at least one of said valves upon failure of the means for eifecting the tight connection between the mould and said pressure chamber.

5. In automatic pressure die-casting apparatus having a mould, a pressure chamber, and means for eflfecting a tight connection between said mould and said pressure chamber, a safety control mechanism comprising, in operative combination, a pressure-admitting valve and an exhaust valve constituting a pair of valves for controlling injection pressure to the pressure chamber, a pair of continually rotating shafts disposed adjacent said valves and supporting a pair of earns, a triple-arm lever pivotally mounted and having one arm depending between said cams, said lever being oscillated by said cams to normally cause the free arms thereof to alternately actuate said pair of valves, and means mounted in said triple-arm lever for intercepting the actuation of at least one of said valves upon failure of the means for effecting a tight connection between the mould and the pressure chamher.

6. In automatic pressure die-casting apparatus having a mould, a pressure chamber, and means for effecting a tight connection between said mould and said pressure chamber, a safety control mechanism comprising, in operative combination, a pressure-admitting valve and an exhaust valve constituting a pair of valves for controlling injection pressure to said pressure chamber, a pair of continually rotating shafts disposed adjacent said valves and supporting a pair of cams, a triplearm lever pivotally mounted and having one arm depending between said cams, a roller rotatably mounted on said depending arm, said roller being adapted to frictionally engage the continually rotating cams to normally cause the free arms of the triple-arm lever to be oscillated, said free arms being adapted to actuate the pair of valves alternately, a slide mounted in said triple-arm lever, resilient means for normally holding said slide in a position to actuate one of said valves, a pawl engaging said slide and adapted to hold the same in a position intercepting the actuation of the aforementioned valve, said pawl being adapted to be disengaged by the mould when the latter is in a position of contact with the pressure chamber, whereby the actuation of the aforementioned valve is permitted.

7. In automatic pressure die-casting apparatus having a. mould, a pressure chamber, means for closing said mould, and means for effecting a connection between said pressure chamber, a safety control mechanism comprising, in operative combination, a pressureadmitting valve and an exhaust valve constitutinga pair of valves for controlling injection pressure to the pressure chamber, a pair of continually rotating shafts disposed adjacent said valves and supporting a. pair of cams, a triple-arm lever pivotally mounted and having one arm depending between said cams, a roller rotatably mounted on said depending arm, said roller being adapted to fricticnally engage the continually rotating cams to normally cause the free arms of the triple-arm lever to be oscillated, said free arms being adapted to actuate the pair of valves alternately, a slide mounted in said triple-arm lever, resilient mould and said means for normally holding said slide in a position to actuate one of said valves, a pawl engaging said slide in a position intercepting the actuation of the aforementioned valve, said pawl being adapted to be disengaged by the mould when the latter is in a position of contact with the pressure chamber, and another pawl also engaging said slide and adapted to hold the same in a position intercepting the actuation of the aforementioned valve, said second-mentioned pawl being adapted to be disengaged when the means for effecting a tight connection between said mould and said pressure chamber has performed its function.

8. In automatic pressure die-casting apparatus having a multipart mould, a pressure chamber, and means for efiecting a tight connection between the individual parts of said mould and between the mould and said pressure chamber, a safety control mechanism comprising, in operative combination, a pressure-admitting valve and an exhaust valve constituting a pair of valves for controlling injection pressure to said pressure chamber, a pair of continually rotating shafts disposed adjacent said valves and supporting a pair of cams, means actuated by said pair of cams for alternately actuating said pair of valves, and means for intercepting the actuation of at least one of said valves upon the failure of any of the aforesaid means for effecting the tight connection between the individual parts of said mould and the means for effecting the tight connection between the mould and said pressure chamber.

9. In automatic pressure die-casting apparatus having a multipart mould, a pressure chamber, and means for effecting a tight connection between the individual parts of said mould and between the mould and said pressure chamber, a safety control mechanism comprising, in operative combination, a pressure-admitting valve and an exhaust valve constituting a pair of valves for controlling injection pressure to said pressure chamber, a pair of continually rotating shafts disposed adjacent said valves and supporting a pair of cams, a triple-arm lever pivotally mounted and having one arm suspended between and actuated by said cams so as to perform an oscillatory movement, said free arms of the triple-arm lever normally actuating the pair of valves alternately, and means mounted in said triple-arm lever for intercepting the actuation of at least one of said valves upon failure of any of the aforesaid means for effecting a tight connection between the individual parts of the mould and between the mould and the pressure chamber to complete its function.

10. In automatic pressure die-casting apparatus having a multipart mould, a pressure chamber, means for closing and establishing a tight connection between the individual parts of said mould, and pressure means for establishing a tight connection between the mould and the pressure chamber, a safety control mechanism comprising, in operative combination, a pressureadmitting valve and an exhaust valve constituting a pair of valves for controlling injection pressure to said pressure chamber, a pair of continually rotating shafts disposed adjacent said valves and supporting a pair of cams, a triple-arm lever suspended between and actuated by said cams so as to perform an oscillatory movement whereby the free arms of the triple-arm lever normally actuate the pair of valves alternately, and means mounted in said triple-arm lever for intercepting the actuation of at least one of said valves upon failure of either of the aforesaid means for closing the mould and establishing a tight connection between the individual parts thereof and the pressure means for establishing a tight connection between the mould and the pressure chamber to complete their function,

11. In automatic pressure die-casting apparatus having a movable multipart mould, a stationary pressure chamber, and means for closing the mould and contacting the mould with said pressure chamber, a safety control mechanism, in operative combination, a pair of valves for controlling injection pressure to said pressure chamber, one valve of said pair being adapted to control the application of pressure to the pressure chamber, the other valve of said pair being adapted to control the exhaust air from said pressure chamber, a pair of continually rotating shafts disposed adjacent said valves and supporting a pair of cams, a triple-arm lever suspended between and actuated by said cams so as to perform an oscillatory movement, a slide mounted in said triple-arm lever, resilient means for normally holding said slide in a position adapted to actuate the valve for controlling the application of pressure to said pressure chamber, a pawl engaging said slide in a position intercepting actuation ofthe valve for controlling the application of pressure to the pressure chamber by the movement of said lever, said pawl being adapted to be disengaged by one part of the mould when the mould is properly closed and in a position of contact with the pressure chamber, whereby actuation of said valve for controlling the application of pressure to said pressure chamber by movement of said triple-arm lever is permitted.

12. In automatic pressure die-casting appa ratus comprising a mould, pressure chamber, and means for effecting a tight connection between said mould and said pressure chamber, a safety control mechanism comprising a pressureadmitting valve and an exhaust valve constituting a pair of valves for controlling injection pressure to said pressure chamber, oscillatory means for alternately actuating said pair of valves, and independent means associated with said oscillatory means for intercepting the actuation of at least one of said valves upon failure of any of the aforesaid means for eiTecting a tight connection between said mould and said pressure chamber to complete its action.

13. In automatic pressure die-casting apparatus having a mould and pressure chamber and means for efiecting a tight connection between said mould and said pressure chamber, a safety control mechanism comprising a pressure-admitting valve and an exhaust valve constituting a pair of valves for controlling injection pressure to said pressure chamber, operating means adapted to normally actuate said pair of valves alternately, continuous driving means for said operating means, and means independent of said operating means for interrupting at least one of said valves upon failure of the means for efiecting the tight connection between the mould and said pressure chamber without interrupting the driving means.

14. In automatic pressure die-casting apparatus comprising a mould, pressure chamber and means for efiecting a tight connection between said mould and said pressure chamber, a safety control mechanism comprising a pressure-ad- 105 mitting valve and an exhaust valve constituting a pair of valves for controlling injection pressure to said pressure chamber, oscillatory means for alternately actuating said pair of valves, and independent means associated with said oscillatory 110 means 'for intercepting the actuation of the pressure-admitting valve upon failure of any of the aforesaid means for effecting a tight connection between said mould and said pressure chamber to complete its action.

KARL FRIEDRICH WAGNER. 

